/**

Definition for singlylinked list.

struct ListNode {

int val;

ListNode *next;

ListNode(int x) : val(x), next(NULL) {}

};
/
class Solution {
public:
/* @param head The linked list's head. Note that the head is guanranteed to be not null, so it contains at least one node. /
Solution(ListNode head) {
h = head;
Len = 1;
ListNode* node = head>next;
while( node != NULL )
{
node = node>next;
++Len;
}
}/** Returns a random node's value. */
int getRandom() {
int n = rand()%Len;
return getNNextNode(n)>val;
}
private:
int Len;
ListNode* h;
ListNode* getNNextNode( int n ){
ListNode* node = h;
while( n > 0 )
node = node>next;
return node;
}
};
/**
 Your Solution object will be instantiated and called as such:
 Solution obj = new Solution(head);
 int param_1 = obj.getRandom();
*/